well you did a good job and you should be proud of it --- Post updated --- i suck at makeing engines XD
Usually what I do is just base the engine off of a real life one, and about half the time it works out ¯\_(ツ)_/¯
I like it how you have crafted parts from bits to make them without mods, it takes some work to put them all nicely together.
Yeah, the only downside to it is that it takes forever. I think I spent half an hour on just the taillights!
Will to put that much effort does make a difference, really good job considering the limitations of available tools! When I made my Stuttgart clone, I did figure out that bumper strips at corner worked out best when they were really short, it has really many of them at rear bumper, might redo front as it has some longer strips, but it is amazing how much one can do with one bumper strip.